The present invention relates to communications, and more particularly, but not exclusively relates to the registration of RF tag devices with an interrogator.
It is becoming more common place to use Radio Frequency (RF) tags for object tracking, product manufacturing, inventory control, merchandising operations, remote sensing, and the like. RF tags are frequently in the form of an electronic device that transmits data in response to an interrogation signal from a reader. Such a device may be “active”—having an independent power source, and/or passive—deriving operational power from the interrogation signal.
In some applications, multiple RF tags are distributed within a region. If the reader has prior information regarding the identity and/or quantity of RF tags within communication range of the reader, the reader can specify that a response be provided only from a certain device or devices; however, sometimes the specific identity/quantity of RF tags within range is initially unknown to the reader. In one form, each RF tag device may be provided with a unique identification code that is transmitted in response to the interrogation signal to distinguish between a number of different devices subject to interrogation by the reader. For such an arrangement, when the reader sends the interrogation signal, there is a possibility that multiple devices will attempt to respond simultaneously, causing a communication collision, and usually an improper message to be received by the interrogator.
Accordingly, various arbitration schemes have been developed to avoid collisions and/or capitalize on the occurrence of communication collisions to identify responding RF tags. However, in some cases, more efficient and/or more cost-effective techniques are desired. Thus, there is an ongoing need for further contributions in this area of technology.